Two months after being sued by Craigslist, 3Taps is standing up to the so-called Internet bully.

Data aggregation company 3Taps filed an antitrust suit against Craigslist in the Federal District Court for Northern California in San Francisco on Monday. 3Taps is accusing Craigslist of non-competitive business practices, saying that the Craiglist's policy of not allowing third party web developers to access information listed on its site is "monopolist" and stifles innovation.

"We want them to respect the fact that public facts are public property and they have strong First Amendment rights," 3Taps founder and CEO Greg Kidd tells Inc. "They're claiming a copyright-like property right over the data which just doesn't exist."

Kidd believes that information posted on Craigslist is in the public domain.

"[Craiglist] allows search engines to index [its information]," Kidd says. "And I'm pretty sure nobody assigned Craigslist the determinant of whether Google is a search engine and Twitter is not."

The suit filed by 3Taps is an answer and counterclaim to a Craiglist action brought against 3Taps and apartment search website PadMapper in July, which accused the companies of violating Craiglist's copyright and trademark. 3Taps, which collects data and then sells it for other companies to use, was providing PadMapper with apartment listings on Craiglist.

This action was the latest instance of Craiglist suing a start-up that tried to build a web application with information culled from Craiglist's listings. Craiglist's litigious nature has garnered infamy from the start-up community.

Kidd--an early investor in Twitter, an advisor to Square and a close friend of Jack Dorsey--is used to breaking what he sees as archaic digital copyright rules.

"The rules are kind of silly, and if you actually look at the laws, there's no basis in law for many of these rules," he says.

Craigslist did not return a request for comment at time of press.

A PDF of 3Tap's answer and counterclaim can be found on the company's home page.